1. Field of the Invention
The present invention relates generally to bushing devices for motor vehicles. More particularly the bushing apparatus is useful for providing a resilient, pivotal suspension attachment capable of sustaining many cycles of considerable axial load without deteriorating the primary isolation function of the bushing device.
2. Disclosure Information
In the conventional motor vehicle, elastic bushings are used at pivotal connections in a suspension, for example, a control arm bushing may be used to pivotally connect the inboard end of the control arm to a structural member of the vehicle frame or body. Generally, the elastic bushings familiar to those skilled in the art comprise outer and inner metallic sleeves coaxially disposed about a resilient member filling the annular space therebetween. The outer sleeve is pressed into apertures in the inboard end of the control arm and a threaded fastener passes through the inner sleeve for connecting the control arm to the vehicle frame or body. In this configuration, the resilient member allows the control arm to pivot about the axis of the threaded fastener, as well as to translate axially and radially, placing the resilient member in shear and compression, respectively.
It has been observed that certain suspension designs may subject attachment bushings to high axial loading, resulting in higher than normal shear force and strain levels within the resilient member. Efforts to minimize the deleterious effects generally have been unsatisfactory, as they have resulted in increased harshness or unacceptable bushing durability.
It would be desirable to overcome the aforenoted difficulties with previous bushing devices for use in motor vehicles by providing a simple, low cost bushing apparatus for attaching a suspension control arm to a structural member capable of reliably operating under many cycles of high axial shear forces while providing desirable harshness and durability characteristics.